Circuit controlling device



May 27, 1952 R. L. KONLE ETAL CIRCUIT CONTROLLING DEVICE 2 SHEETS-SHEET 1 Filed Oct. 16, 1950 NORMAL.

CONTINUOU S RUN I P-r M y 1952 R. L. KONLE EI'AL 2,598,563

CIRCUIT CONTROLLING DEVICE Filed Oct. 16, 1950 2 SHEETS-SHEET 2 NORMAL. 1 CYCLJNG 80 RANGE.

Patented May 27, 1952 CIRCUIT CONTROLLING DEVICE Robert L. Konlc, New Berlin Township, Waukesha County, and Clarence W. Kuhn, Wauwatosa, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application October 16, lilberial No. 190,262

1 Claims. 1

This invention relates to circuit controlling devices and more particularly to automatic temperature control switches for use in connection with electric refrigerators to control a plurality of circuits, one of which is adapted to control an I alarm device to indicate abnormal temperatures within the refrigerator.

The invention has among its objects the provision in a switch of the aforementioned character of a single manual setting means affording in the switch the three-way function of normal cycling, continuous run, and alarm off" positions. 1

Another object of the invention is the provision of novel manual switch setting means for controlling all of the switch functions and more particularly provision of a manual switch setting means having operating positions as follows: (1) a normal position wherein the switch functions normally to govern the supply of energy to the refrigerator to maintain the same within a predetermined temperature range, but permits commutation of an alarm circuit at a predetermined abnormal temperature; (2) a continuous run position wherein the main switch contacts are biased to closed position regardless of temperature, but the alarm circuit contacts function to commutate an alarm circuit at essentially the same predetermined abnormal temperature as in the first position; and (3) an alarm off position wherein the switch is free to function as in the first position, but the contacts in the alarm circuit are biased to a given position regardless of temperature.

Another object is to provide switch setting means affording the aforementioned functions which are simple and rugged in construction and which may be incorporated in a switch of relatively small proportions, particularly with respect to its front to back dimension, without increase in the size of the switch, thereby affording an exceedingly thin switch from front to back adapted for mounting in the wall of a refrigerator.

Various other objects and advantages of th invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that various modificationsmay be made in the embodiment illustrated without departing from the spirit and scope of the appended claims.

In the drawings,

Figure 1 is a top plan view of the control switch embodying the invention, with operating parts of construction and operation thereof.

removed and the cover partially broken away;

Fig. 2 is a center line section taken substantially on line 2-2 of Fig. 1, with the switch parts shown in alarmofF' position;

Fig. 3 is a detail side elevation of one of the switch levers;

Fig. 4 is a lateral section taken substantially on line 4-4 of Fig. 2;

Fig. 4 is a fragmentary section illustrating a modified form of alarm contacts;

Fig. 5 is a fragmentary sectional view, with the 'cover and operating parts spaced away from certain of the other switch parts for clarity o illustration;

Fig. 6 is a detail top plan view of the cup memher; and

Fig. 7 is a schematic illustration showing the range of movements.

The refrigerator control switch illustrated in the drawings includes a switch unit l0 and a unitary operating assembly therefor, including a snap acting operating mechanism I I and a pressure responsive device I2, all of substantially the type disclosed in the Kuhn Patent No. 2,511,640 to which reference may be had for the details It is deemed desirable here to note merely that the switch unit III includes stationary contacts III to be connected in circuit with the supply of electrical energy for the refrigerator motor for control thereof in the usual manner, said circuit to be opened and closed by bridging of contacts III by a contactor III normally biased to closed circuit position by a spring III.

The snap acting mechanism under the control of the pressure responsive device I2 is of the type disclosed in the patent to C. F. Robbins, No. 2,375,387, to which reference may be had for the details of its construction and operation, it being here necessary merely to note that contactor III is actuated by pressure responsive device I2 through the snap acting mechanism II consisting generaly of an operating lever II. a control lever II", and over-center springs II.

As will be apparent, expansion of the pressure responsive device I2 is opposed by a loading spring I3 associated therewith, the snap acting means I I being responsive to expansion and contraction of the pressure responsive device I2 for actuation of the main contactor II! in the usual manner.

Additionally, the switch unit III is provided with a set of auxiliary contacts I4 (Figs. 2 and 4) for controlling a circuit to an alarm device (not shown) utilized in the refrigerator to indicat abnormal or dangerous temperatures therein. Such an alarm device may be a bell, a buzzer, a light, or the like, and if the latter, might be connected to light up to indicate abnormal refrigeretor conditions, or to go out upon the incidence of abnormal refrigerator conditions. The auxiliary contacts Il may therefore be of the normally open type as illustrated in Fig. 4 or of the normally closed type as illustrated in Fig. 4'.

More specifically, the auxiliary contacts I4 of the normally open type shown in Fig. 4 comprise an adjustable stationary contact II and a movable contact I4 carried by an insulating member |4 adapted to reciprocate within a recess in the base of switch unit I0, a helical spring M positioned within the same recess biases the member I4 and contact M carried thereby upwardly and additionally spring M serves to carry current from a terminal screw I5"- (Fig. 4), to

which it is electrically connected, to the contact M The stationary contact I4, as best shown in Fig. 4, is electrically connected to terminal screw I5 As best illustrated in Fig. 2, member I4 carrying the contact M is movable downwardly against its bias into contact with stationary contact I4 by a lever I6 pivoted as at I6, one end of said lever extending into the switch operating compartment to engage a cup I'I (to be hereinafter described) movable upwardly in response to expansion of the pressure responsive means I2.

In the modification of the auxiliary contacts I4 to afford a normally closed relationship as illustrated in Fig. 4, the stationary contact I4 is formed with an enlarged head at the upper end thereof, and the insulating member I 4 is provided with a downwardly opening recess in which the head of contact M is free to reciprocate. A washer-like annular member M serving as the movable contact is carried by the spring M and affords clearance for the contact N the head of which overlies member M As will be apparent, the spring M normally maintains the contact members I4 and N in in Fig. 5, is adapted in the other extreme position of the manual setting means, to engage a tail extension I on control lever II of the snap acting mechanism I to prevent movement of the latter permitting opening of the main contacts I0, I0 thereby affording a continuous run" position as will hereinafter be described.

Pivotally attached to the enclosing casing of the switch is a lever 24 best shown in Figs. 1 and 5 overlying loading spring I3 and having a clearance hole 24 affording projection therethrough of pin 23. As best shown in Fig. 5, lever 24 is additionally provided with an upwardly extending boss 24 for engagement with a detent 22" (Figs. 1, 2 and 5) in member 22 when the manual setting means is moved to the continuous run" position, such engagement restraining movement of the setting means out of that position when moved thereto.

As aforementioned, the cup I1 is movable upwardly and downwardly with expansion and contraction of the temperature responsive means carrying pin 23 through a corresponding range of movement. Referring to Figs. 2, 4 and '7, upward movement of the cup I'I with expansion of temperature responsive means I2, due to increase of temperature in the refrigerator, first causes movement of snap acting means II to' actuate main contacts I0, Ill to closed circuit position, the temperature at which such closure is effected being the "trip-on temperature of the switch (Fig. 7). Assuming the temperature in the refrigerator then to decrease, the temperature responsive means will again contract and cup U will move downwardly under the bias of loading spring I3. Upon a given degree of downengagement, but when member I4 is moved 4 downwardly by action of lever I6, the member H forces contact M downwardly against the bias of spring M to effect disengagement of contacts N and contact Il the recess in member I4' affording clearance for the head of contact M as aforementioned.

The control device aforedescribed is further provided with a single manual setting means affording a three-way function as hereinafter described, said setting means comprising a shaft I8 (Fig. 2) rotatably mounted on the cover member of the switch mechanism and extending both internally and externally thereof. Rigidly affixed to the external end of shaft I8 is a coupling member I9 carrying a molded operating knob 20; while rigidly attached to the opposite end of the shaft I8 inside of the cover member are a cam member 2| and a--washer member 22, the latter two members being jointly rotatable upon rotaward movement, the snap acting mechanism II will again open the main switch contacts, the temperature at which such opening takes place being the trip-off temperature of the switch (Fig. '7) This automatic recurring operation of the switch with changes in temperature is termed the normal cycling of the switch.

If, however, after the "trip-on temperature has been reached and the temperature in the refrigerator still continues to rise thereby resulting in further upward movement of cup II, the latter, upon a given degree of overtravel will move lever IS with which it is in engagement to effect actuation of the auxiliary contacts I4, thereby affording an indication of the abnormal temperature in the refrigerator. In this connection it will be noted that the stationary contact I4 is in the form of a screw permitting adjustment of the point of over-travel of cup II, hence the temperature, at which the contacts I4, I 4* will engage.

The foregoing description of operation of the control mechanism of course, obtains only if cup I! and pin 23 carried thereby are free to move through the entire range of movement as indicated in Fig. 7, and if the snap acting mechanism I I is free to respond as intended. Such freedoms are, however, governed by the setting of the manual setting means, and only in the intermediate or normal.position thereof are both the snap acting mechanism and the cup I1 permitted complete freedom of movement throughout their entire range.

As best shown in Fig. 5, when the manual setting means are in the continuous run position, the snap acting mechanism is not free to operate because of the engageemnt of lug 2 I with the tail extension I I of operating lever l thereby preventingopening of the main contacts I0, I0 As aforementioned, the boss 24 on lever 24 engages the detent 22 of member 22 in this position of the manual setting means to insure maintenance of the setting means in this position regardless of the movement of cup l1 and pin 23. As will be apparent, the latter are free to move throughout their full range in response to movement of pressure responsive means l2 with changes in temperature in the refrigerator. Therefore, should the refrigerator temperature rise to an abnormal degree, the auxiliary contacts ll may be actuated to cause indication of such abnormal temperature. Since the loading of spring I3 has remained substantially the same, such abnormal temperature will be the temperature predetermined for operation of the auxiliary or alarm contacts 14 when the manual settin means is in normal position.

If, however, the manual setting means is moved to the alarm off position, as best shown in Fig. 2, the cam surface 2| of member 2| will be in position to block over-travel of cup I! and pin 23 by engagement of the latter with the cam surface 2|, thereby preventing actuation of the auxiliary or alarm contacts i4. As will be apparent, such blocking of the parts to prevent alarm indication is necessary to prevent such indication when the refrigerator is pulling down from an abnormal temperature, as for example when the refrigerator is first put into operation. It will be noted, however, that while cam surface 2| prevents over-travel of cup I! and pin 23, as aforementioned, it permits movement of those parts freely between the trip-on and trip-off points of the main contacts, as shown in Fig. 7, thus permitting the refrigerator to cycle within its normal temperature range.

As will be apparent, the foregoing requires close control over the distance between the cup I! (or top of pin 23 carried thereby) and the cam surface 2!. Since maintenance of such close control is beyond the normal tolerances of these parts, it has been found desirable to make cup I! of special design. As best shown in Fig. 6, cup I1 is formed with a bendable web IT in which the pin 23 rides (Fig. 2). This web is bent in a fixture during assembly in order to produce the desired relationship, in so far as spacing is concerned, between the pin 23 and cam surface Zi in order to effectively block alarm contact action without interfering with normal cycling of the main conr tacts.

Referring to Figs. 2 and 5, it will be seen that pin 23 is threaded and carries a nut 25 upon which the loading spring l3 rides, and that pin 23 is recessed at the upper end thereof as at 23 to afford a socket for a suitable wrench. The loading of spring [3 may be adjusted by turning pin 23 to run nut 25 up or down, as the case may be, to change the range of normal cycling of the switch. The differential between the trip-on and trip-off points of the switch may be adjusted by means of a differential screw 26 limiting movement of the lever H of the snap acting close or open said main contacts at predetermined temperatures, a set of auxiliary contacts actuated by said pressure responsive means upon over-travel thereof, a single manual switch setting means having a plurality of operative positions, said manual setting means including means which in a first position of the setting means block movement of said actuating mechanism to maintain said main contacts in a given position but afford freedom of movement of said pressure responsive means throughout its full range, and means blocking over-travel of said pressure responsive means but permitting normal movement of said actuating mechanism in a second position of said manual setting means, the latter in a third operative position permitting complete freedom of movement of both said actuating mechanism and said pressure responsive means for normal cycling of the switch and actuation of said auxiliary contacts upon over-travel of said pressure responsive means.

2. In combination, a thermal responsive switch having a set of main contacts, an actuating mechanism therefor and pressure responsive means controlling said actuating mechanism to close or open said main contacts at predetermined temperatures, a set of auxiliarycontacts actuated by said pressure responsive means upon over-travel thereof, a single manual switch setting means having a plurality of operative positions, said manual setting means including means which in a first position of said manual setting means block movement of said actuating mechanism to maintain said main contacts in a given position but afford freedom of movement of said pressure responsive means throughout its full range, means for maintaining said manual setting means in said first position regardless of response of said pressure responsive means, and means blocking over-travel of said pressure responsive means but permitting normal movement of said actuating mechanism in a second position of said manual setting means, the latter in a third operative position permitting complete freedom of movement of both said actuating mechanism and said pressure responsive means for normal cycling of the switch and actuation of said auxiliary contacts upon over-travel of said pressure responsive means.

3. In combination, a thermal responsive switch having a set of main contacts, a snap acting actuating mechanism therefor and pressure responsive means controlling said mechanism to open and close said main contacts at predetermined cut-in and cutout temperatures, a set of auxiliary contacts actuated by said pressure responsive means upon travel thereof beyond said predetermined temperatures, a single manual switch setting means having at least three operative positions, said manual setting 'means including means for blocking movement of said snap acting mechanism to maintain said main contacts closed to afford a continuous run position of the switch but affording freedom of movement of said pressure responsive means throughout its full range to actuate said auxiliary contacts upon overtravel of said pressure responsive means, means blocking over-travel of said pressure responsive means to prevent actuation of said auxiliary contacts but permitting normal movement of said snap acting mechanism and commutation of said main contacts in a second position of said manual setting means, the latter in a third operative position permitting complete freedom of movement of both said snap acting mechanismand said means controlling said actuating mechanism to a close or open said main contacts at predetermined temperatures, a set of auxiliary contacts actuated by said pressure responsive means upon over-travel thereof, a single manual switch setting means having a. plurality of operative positions, said manual setting means including an adjusting member having a cam surface and a lug extension, said lug extension in a first operative position of said manual setting means meeting with said actuating mechanism to move the latter to a given position but permitting movement of said pressure responsive means throughout its full range, means for maintaining said given position, said cam surface of said adjusting member in a second operative position of said manual setting means blocking over-travel of said pressure responsive means to prevent actuation of said auxiliary contacts but permitting normal movement thereof for operation of said actuating mechanism to open or close said main contacts. said lug and said cam surface in an intermediate position of said manual setting means being disengaged from their aforementioned coacting parts to permit free movement of both said actuating mechanism and said pressure responsive means for normal cycling of the switch and actuation of said auxiliary contacts upon over-travel of said pressure responsive means.

5. In combination, a thermal responsive switch having a set of main contacts, a snap acting actuating mechanism therefor and expandible pressure responsive means for actuating said mech-' anism to open and close said main contacts at predetermined cut-in and cut-out temperatures, a set of auxiliary contacts actuated by said pressure responsive means upon over-travel thereof beyond said cut-in temperature, a single manual switch setting means having three operative positions, said switch setting means including a rotatable adjusting member having a cam surface and a lug extension, said lug extension in a first operative position of said switch setting means coacting with said snap acting mechanism to lock the latter in a given position to maintain said main contacts closed, said cam-surface in a sec- .ond operative position of said switch setting means coacting with said pressure responsive means to block over-travel thereof beyond said cut-in temperature thereby preventing actuation of said auxiliary contacts, said lug and said cam surface in an intermediate position of said switch being disengaged from their aforementioned coacting parts to permit free movement of said pressure responsive means and said snap acting mechanism thereby affording opening and closing of said main contacts at said cut-in and cut-out temperatures and commutation of said auxiliary contacts at a predetermined temperature above said cut-in temperature.

ROBERT L. KONLE.

CLARENCE W. KUHN.

REFERENCES CITED UNITED STATES PATENTS Name Date Bauman Aug. 24, 1948 Number 

